The present invention relates to improvements in facilities for maintaining drains in commercial kitchens.
In cooking environments, various items are discharged into a drain, not the least of which is grease, a by-product from cooking and washing. Grease in particular can be a source of problems, because when it cools, it can congeal and solidify, forming a solid having the capability of blocking or constricting the drain. Such grease blockage can build up over time, so it does not usually represent a discrete blockage event, but rather an accretion of congealed grease on the insides of the drains that, over time, narrows the flow path through the drain. This leads to the possibility of slow flow and, more particularly, to a possible blockage caused by a small article that would not block an unrestricted drain.
In addition, grease/water mixtures disposed directly into sewer lines burden municipal sewage systems since the grease builds up in sewer lines and on equipment in sewage treatment plants. To offset maintenance costs resulting from direct grease discharges into municipal sewers, municipal authorities assess surcharges against commercial food preparation operations that directly discharge grease/water mixtures.
Most food disposal installations in commercial kitchens involve a pre-rinse station in the dishwashing area. Dishes arriving from the dining area are first brought to the pre-rinse station where the food solids are rinsed into the pre-rinse sink and drain into the food disposal. Currently available technology does not provide for the separation of grease and oils prior to maceration by the food disposal unit. These flows frequently harbor high levels of fats (from salad dressings, butter, margarine, and fatty food scraps). As a result, food disposals are banned from commercial usage in numerous cities in the USA and around the world.
The advantages of garbage/food disposals are well known, so that the banning of such equipment brings additional problems of waste disposal, hygiene, and sanitation to commercial kitchen operations. Such operations need a solution to the problem of complying with sewer district needs while avoiding these untoward consequences.
The present invention fulfills this need in the art by providing a food disposal system for installation on a drain of a commercial kitchen sink to enable segregation of oil/grease from effluent flows from the drain. A housing collects effluent flows containing water, oil/grease, and solids from the drain. A macerating pump has an inlet connected to an opening of the housing and an outlet connected to a sanitary drain. A greasy water outlet extends to an oil/grease separator from the housing above the macerating pump inlet. A hot water backflush source enables hot water to flow into the housing. A sensor may sense the accumulated oil/grease in the housing. A controller effects the operation of the hot water backflush and macerating pump.
A screen may be interposed between the outlet and the housing. The hot water backflush may direct hot water against the screen.
The housing may be configured as a chute with the macerating pump located at a chute bottom. In such an embodiment, the outlet to the sanitary drain may include a channel extending upwardly. The greasy water outlet is typically located at the static water level.
The oil/grease separator may itself include a macerating pump to macerate solids that travel to the oil/grease separator.
In one embodiment the controller is a timed controller. A sensor may be included for sensing accumulated oil/grease in the housing, and the controller may effect the operation in response to the sensor sensing the oil/grease causing a water backup to a particular level. If the outlet to the sanitary drain includes a channel extending upwardly, the sensor may be located in the outlet to the sanitary drain above the static water level so that it senses a raised water level caused by an accumulation of oil/grease. Alternatively, the outlet to the sanitary drain may include a channel extending upwardly to define a secondary static water level with the sensor located in an upper portion of the housing below the secondary static water level so that it senses a raised water level caused by an accumulation of solids.
A cold water source may be included actuable to introduce cold water into the housing when the macerating pump is operated.
The controller may be an operator-actuable switch.
In one embodiment the greasy water outlet includes a running gas trap assembly.
The invention also provides a fitting for installation on a drain of a commercial kitchen sink to enable segregation of oil/grease from effluent flows from the drain. The fitting includes a housing for collecting effluent flows containing water, oil/grease, and solids from the drain. An opening on the housing is adapted to be connected to a macerating pump, and a greasy water outlet on the housing above the opening is adapted to be connected to an oil/grease separator. The housing also has a hot water backflush fitting adapted to be connected to a hot water source for enabling hot water to flow into the housing. A controller may be included adapted to be connected for effecting the operation of the hot water backflush and macerating pump. In a preferred embodiment the housing includes a chute with a bottom, with the opening near the chute bottom.
The invention also provides a method of segregation of oil/grease from effluent flows of a drain of a commercial kitchen sink including draining the effluent flow containing water, oil/grease, and solids from a commercial kitchen sink to a housing below the sink, allowing gravitational separation of lighter components from heavier components of the effluent flow to take place in the housing, directing lighter components of the effluent from the housing to an oil/grease separator, and periodically operating a macerating pump having an inlet connected to the housing to pump and macerate the heavier components and direct the heavier components to a sanitary drain.
The method may include maintaining a static water level at an elevation in the housing above the inlet. Directing the lighter components includes permitting gravitational flows of the lighter components from the housing at a height in the housing at the static water level. The gravitational separation of components of the effluent flow may include permitting heavy solids to travel down a chute to the inlet of the macerating pump.
The separation of lighter components from heavier components of the effluent flow may include screening solids from traveling with the lighter components. If so, the method may also include periodically directing hot water flows against a screen to loosen grease-bound solids from the screen. The hot water may be directed against the screen when a water level sensor indicates a rising water level.
Typically, the macerating pump is operated after the hot water is directed against the screen. Cold water may be introduced into the housing when the macerating pump is operated.
The macerating pump may be operated by a timer. Alternatively, the macerating pump may be triggered by a manually operated switch or a level detector.